Search Results (803)

Wood, a renewable and sustainable resource with a hierarchical porous structure, exhibits significant potential for functional composites through integration with polymers. Wood/polymer composites are typically fabricated either via polymer impregnation into wood or through blending of wood powder with thermoplastic polymers to produce wood–plastic composites (WPCs). However, conventional thermosetting polymers cannot be reshaped or reprocessed, while thermoplastic polyolefins often exhibit poor compatibility with wood powder. Dynamic covalent polymer networks (DCPNs), which incorporate reversible covalent bonds into thermoset matrices, enable network reconfiguration in response to external stimuli such as heat. Replacing conventional polymers with DCPNs in delignified wood yields transparent wood with programmable shape-memory, photo-luminescent, and thermochromic properties, enabling the fabrication of advanced materials. DCPN-impregnated delignified wood is also reprocessable and degradable. Similarly, incorporating DCPNs into carbonized wood produces electrode materials with enhanced plasticity, shape-memory behavior, reshaping ability, and self-healing properties. DCPNs can replace thermoplastic polyolefins as matrices in WPCs. Consequently, repairable and reprocessable wood powder/DCPN composites can be fabricated with potential for carbon storage applications. This mini-review summarizes recent advances in wood/DCPN composites, focusing on two main fabrication approaches: DCPN impregnation into delignified wood and blending of DCPNs with wood powder. Wood/DCPN composites combine the characteristics of wood and dynamic DCPNs and have the potential to become an efficient, eco-friendly, and sustainable form of processing and utilization of wood. Full article

More than 95% of building materials in Europe are produced from fossil raw materials. Over the past two decades, numerous scientific studies have demonstrated that building materials made from agricultural plants or industrial processing waste can compete with traditional materials. In this work, engineered wood composites were prepared from biopolyurethane and barley straw, and their properties were evaluated. Barley straw from bales was milled through sieves of different sizes. Four straw fractions of 5, 10, 25 and 35 mm were prepared for testing. During the research, the granulometric composition, particle density and shape of various fractions were evaluated. Engineered wood composites were prepared using different filler fractions and a biopolyurethane binder. In this study, engineered wood samples were produced using biopolyurethane binders at straw-to-binder ratios of 0.5 to 1.5. Different pressure levels were used for sample preparation: 1.5, 2.25 and 3.0 MPa. This study evaluated the influence of the granulometric composition and particle shape of straw on the properties of engineered wood composites. Tests showed that the highest compressive strength, 17.0 MPa, was achieved with composites formed from a 5 mm straw fraction, which had the highest density. The samples with the highest density were also characterised by the lowest swelling (5–10%) and water absorption (1–2%). The flammability of the samples showed that at a 0.5 binder/straw ratio, the composite was non-combustible and did not support flame spread after the flame source was removed. Full article

Dowel-laminated timber (DLT) is a composite structural material manufactured entirely from wood. Increasing awareness of the sustainability, end-of-life recyclability, and potential health concerns associated with synthetic adhesives used in cross-laminated timber (CLT) and glulam has intensified industry and academic interest in adhesive-free mass-timber systems like DLT. In Australia, however, DLT remains under-researched. This paper addresses global and local knowledge gaps by developing a linear-elastic numerical modelling method for DLT using Australian finite element analysis software Strand7 and investigating structural optimisation strategies, including the use of Australian hardwoods. A finite element model captured the characteristic response of a DLT beam from the University of Liverpool within the linear-elastic range. Reduced dowel spacing, alteration of lamella thicknesses and targeted dowel placement in the shear zones increased global stiffness in the parametrisation study. Incorporating Australian hardwood in the outer lamellae further improved bending performance. Structural viability in the Australian context was indicated through the design of a project-scale DLT beam prototype assessed to relevant Australian Standards. The modelling approach and findings are presented alongside a discussion of behavioural nuances, contributing to the growing body of research on DLT. Full article

Wood-based panels are increasingly used in exterior applications; however, comprehensive evaluations of their durability under standardized aging conditions remain limited. This study evaluates the dimensional stability and mechanical performance of three industrial panels designed for exterior use: a three-layer particleboard (PB1) and a single-layer particleboard (PB2), both bonded with phenol–formaldehyde adhesive, and a medium-density fibreboard (MDF), bonded with polymeric methylene diphenyl diisocyanate through accelerated aging. The panels were subjected to six accelerated aging cycles according to the ASTM D1037-12 (2020) standard. Equilibrium moisture content, residual thickness swelling (Residual-TS), bending modulus of rupture (MOR), modulus of elasticity (MOE) in both parallel and perpendicular directions, and internal bond (IB) strength were measured under aged and non-aged conditions. PB2 demonstrated superior dimensional stability (Residual-TS: 0.49%) and strong mechanical retention (MOR: 67%, MOE: 56%–64%, IB: 75%). PB1 showed intermediate dimensional stability and mechanical retention (Residual-TS: 1.58%; MOR: 66%–74%, MOE: 56%–58%, IB: 71%), while MDF exhibited higher sensitivity to aging, with excessive Residual-TS (5.43%) and lower IB strength retention (30%). Specimen orientation did not affect dimensional stability but did influence the bending properties of the particleboard after aging, specifically MOR in PB2 and MOE in PB1. The results demonstrate that PB2 offers superior performance for demanding exterior applications, while PB1 and MDF are suitable for semi-protected uses. All panels were tested in an unfinished state, although surface coatings in actual applications may further enhance the resistance to aging. Full article

Industrial control of volatile organic compound (VOC) emissions from medium-density fibreboard (MDF) production remains constrained by a shortage of compound-resolved evidence from full-scale plants, where wood furnish, amino resin chemistry, heat transfer, gas flow, and wet gas cleaning act simultaneously. Here, we analysed more than 20,000 synchronized operating records from a full-scale single-stage flash-tube MDF dryer at an industrial SWISS KRONO production line and linked total VOC (TVOC) measurements from flame ionization detection with Fourier-transform infrared speciation on the cleaned stack. Five compounds—α-pinene, 3-carene, limonene, methanol, and formaldehyde—accounted for more than 80% of the resolved VOC signal. Process–state contrasts showed that higher digester residence time, discharge screw speed, adhesive amount, urea amount, dryer inlet temperature, and scrubber–water temperature increased one or more representative compounds, whereas higher hardwood share, additional flue-gas supply, and higher scrubber–water pH decreased them. Limonene, methanol, and formaldehyde were substantially more process-sensitive than α-pinene. An exploratory decorrelation step further showed that a drying/throughput domain explained about half of the variability of the screened process space. The study therefore identifies the small set of compounds and operating domains that most strongly govern the cleaned dryer-stack signature and provides a mechanistically grounded prioritization framework for follow-up causal experiments, source apportionment, and emission-mitigation design in industrial MDF manufacture. Unlike product or chamber emission studies, this work links the compound-resolved FTIR/FID chemistry of the final cleaned industrial stack with synchronized production variables; it therefore addresses a scale-integration gap by transforming routine compliance-type exhaust monitoring into a process-diagnostic framework for ranking emission sources, abatement-sensitive variables, and mitigation experiments. Full article

The construction sector’s drive for sustainability has increased the use of Cross-Laminated Timber (CLT), yet its structural reliability is governed by the integrity of the adhesive bond line. This study evaluates the influence of three one-component polyurethane (PUR) formulations (R1, R2, R3) on the adhesion performance of maritime pine CLT. To isolate adhesive-related effects, lamellas were mechanically classified by modulus of elasticity (MOE) and randomly allocated within stiffness classes. Adhesive characterization through ABES, FTIR, and DSC revealed that R3 exhibited slower cure kinetics (t₀ = 5482 s) but higher thermal stability. Mechanical testing showed that all formulations developed structurally effective dry bonds with shear strengths exceeding 7.1 MPa, with R3 achieving significantly higher dry shear and interlaminar strength. However, 24 h water immersion caused a catastrophic strength reduction exceeding 95% across all formulations, shifting the failure mode from the wood substrate to the adhesive layer. DSC analysis identified glass transition temperatures between 28 °C and 32 °C, which are consistent with the potential for moisture-induced plasticization near service temperatures. These results indicate that while slower-curing formulations like R3 enhance bond quality in dense softwoods due to improved interphase formation, all evaluated PUR systems showed significant vulnerability to saturated conditions, suggesting that adequate moisture protection is essential for maritime pine CLT applications. Full article

To promote circular economy in construction, this study evaluates the mechanical surface integrity and long-term water durability of sustainable low-density particleboards utilizing agro-forestry residues, such as corn cob, corn stalk, hemp shive and wood fibres. These are bonded using an ecological mimosa tannin adhesive in comparison to a conventional urea–formaldehyde-based adhesive. Performance was assessed through apparent density, surface cohesion, Shore A hardness and impact resistance. Furthermore, the water sensitivity was assessed through total water absorption (WA), thickness swelling (TS), and a customized cyclic immersion-drying protocol. Results showed a significant correlation between density and Shore A hardness (R² = 0.77). While hemp- and corn-based boards showed surface performance competitive with commercial standards, the wood fibre series exhibited extreme water susceptibility, with mass variations exceeding 400% during cycling. Additionally, tannin-based boards showed evidence of leaching, with an 11% mass loss after three emersion cycles. These findings conclude that while tannin adhesives are viable renewable alternatives, these bio-boards are primarily suited for interior lining in dry environments, as lightweight formulations require additional protection to ensure durability in practical building applications. Full article

To investigate the bonding performance between Northeast larch (Larix gmelinii) and carbon fiber-reinforced polymer (CFRP) as well as basalt fiber-reinforced polymer (BFRP), this paper systematically analyzes the effects of fiber-reinforced polymer (FRP) type, bonding length, and bonding width on the mechanical behavior of the interface through single shear pull-out tests. A total of 20 FRP-timber specimens were designed for the tests, and their ultimate bearing capacity, failure mode, strain distribution, and load-slip relationship were measured. The results indicate that BFRP exhibits greater ductility, averaging 35.04% higher than CFRP, while CFRP demonstrates significantly higher tensile strength, exceeding BFRP by 83.41%. The failure mode of CFRP specimens primarily involves debonding at the timber-adhesive interface, whereas BFRP specimens mainly exhibit debonding at the FRP-adhesive interface. An increase in bonding width leads to a larger bonding area, resulting in a higher ultimate load capacity. However, due to the limitations of effective bonding length, the ultimate load increases rapidly when bonding length is raised from 50 mm to 100 mm, but further increases in length yield diminish returns in load capacity. Strain distribution analysis reveals that the strain in FRP decreases linearly along the bonding length, with peak strain increasing as bonding width decreases. Based on the experimental data, a predictive model for interfacial debonding load capacity was developed, demonstrating good robustness with an average coefficient of determination (R²) of 0.65. This model provides a reliable theoretical reference for evaluating the ultimate load capacity of FRP-reinforced Northeast larch structures, while also offering essential experimental evidence and theoretical support for FRP reinforcement design in Northeast larch wood structures. Full article

This bibliometric study examined 179 Scopus-indexed publications on the physical and mechanical properties of medium-density fiberboard (MDF) published between 2016 and 2025. BiblioMagika^® was used for performance analysis, and Biblioshiny was used for keyword co-occurrence, thematic mapping, and thematic evolution. The papers identified as the cohort for analysis had received 2830 citations in total, with an average of 15.81 citations per paper, and an average h-index of 30. The European Journal of Wood and Wood Products and BioResources were the most productive sources. Three distinct categories were identified through keyword mapping among the studies reviewed: (1) advanced composites and reinforcement, (2) adhesive and emission-related studies, and (3) circular-material strategies. Thematic evolution showed a trend away from traditional resin-performance topics toward broader sustainability-related themes, particularly bio-based adhesives and recycling-related topics. Overall, this review provides a quantitative overview of publication patterns, influential sources, and thematic development in MDF research. It also provides direction for future MDF research, focusing on durability, large-scale feasibility, life-cycle assessments, and practical implementation. Full article

The limited availability of high-quality timber and the increasing demand for wood-based panels have encouraged the exploration of alternative and sustainable lignocellulosic resources. Rattan waste is abundant in Indonesia; however, its low mechanical strength and limited durability restrict its direct application in composite materials. This study investigated the effect of furfuryl alcohol (FA) modification and different adhesive systems on the performance of rattan-based particleboard. Rattan particles were immersed in FA for 24 h and used to produce particleboards (300 × 300 × 10 mm) bonded with phenol formaldehyde (PF), melamine formaldehyde (MF), and urea formaldehyde (UF) adhesives at a resin content of 12%. The boards were manufactured under controlled hot pressing conditions and conditioned for 14 days prior to testing. Furfurylation significantly improved dimensional stability by reducing moisture content, water absorption, thickness swelling, and leaching, with anti-swelling efficiency values ranging from 43.25% to 71.06%. Some selected mechanical properties, including internal bonding strength, hardness, and screw holding power, were also enhanced. However, the modification showed limited influence on the modulus of elasticity and, in some cases, reduced the modulus of rupture. Among the adhesive systems, MF-bonded boards exhibited the most balanced mechanical performance. Furfurylation also produced darker and more uniform board surfaces. These findings indicate that furfurylated rattan particleboards are suitable for non-structural and decorative applications. Full article

Engineered wood products manufactured with the durability and density of a Pinus radiata D. Don species usually do not achieve the mechanical properties of a structural material for construction; hence, the reinforcement of this kind of product is recommended, but the use of commonly used hazardous adhesives is a problem. Therefore, the primary objective of this research was to investigate the enhancement of various properties of glulam beams made from radiata pine through the application of a high-performance reinforcing composite, based on carbon fiber, polyvinyl alcohol, and other nanomaterials, at a laboratory scale. For this purpose, thermal and mechanical tests were performed in different composite formulations to choose the best ones and to manufacture the glulam beams, in which bending properties were measured. Based on the results, the samples reinforced with graphene stood out, and the samples mixed with epoxy resin presented statistically the same values of flexural stiffness and strength as the control samples elaborated with commercial wood adhesives. It is also important to highlight the performance of the samples M7 (PVA (7.5%) + NL (0.01%) + GP (0.01%) + NSiO₂ (0.01%)) and M8 (PVA (7.5%) + NL (0.01%) + GP (0.01%) + NTiO₂ (0.01%)), which are not mixed with epoxy resin and showed statistically the same flexural performance as epoxy resin, in terms of maximum load and displacement. As a conclusion, it could be said that this new high-performance composite could be a comparable alternative to hazardous commercial adhesives, by obtaining lower values, but close to those of the control sample, which are the most used when reinforcing wood products with engineering fibers. Full article

This study developed poly(lactic acid) (PLA) biocomposites reinforced with pine wood flour (10, 20, and 30 wt%) to achieve the interphase through chemical modification. Specifically, the wood flour was treated with poly(propylene glycol) toluene 2,4-diisocyanate terminated (PEGTDI), while 1 wt% poly(lactic acid)-g-maleic anhydride (PLA-g-MA) was integrated as a reactive compatibilizer during extrusion and thermocompression. Fourier-transform infrared spectroscopy (FTIR) analysis corroborated the occurrence of urethane formation and ester/anhydride linkages, as substantiated by the presence of characteristic bands indicative of surface carbamation at 1645 and 1726 cm⁻¹. Thermal analysis revealed that both the pine wood flour and coupling agents promoted PLA crystallization; however, thermogravimetric analysis (TGA) indicated a decrease in thermal stability for functionalized composites, suggesting a trade-off between enhanced interfacial interaction and heat resistance. Mechanical testing demonstrated a significant reinforcement effect, with the Young’s modulus increasing by up to 22% in untreated composites. The coupling agents effectively optimized stress transfer at low fiber loadings (10 wt%), while flexural modulus improvements were predominant at higher loadings (20–30 wt%) regardless of treatment. These findings underscore the criticality of surface modification and compatibilizer selection for tailoring the structural and thermo-mechanical properties of PLA-based biocomposites, thereby providing a pathway for optimized performance in structural applications. Full article

To develop a fully green and non-toxic wood adhesive with improved water resistance and bonding performance for soybean meal (Glycine max (L.) Merr.)-based adhesives, oxidized tannin (OTN) was obtained by the laccase treatment of waxberry tannin (TN), a natural polyphenolic polymer, and then blended with soybean meal (SM) to prepare an oxidized tannin–soybean meal adhesive (OTS). Laccase-mediated oxidation converted the tannin polymer into quinone-rich oxidized polymeric structures, which reacted with amino groups in soybean meal proteins through Michael addition and Schiff base reactions to form a covalently crosslinked polymeric network. Under the optimal conditions of a laccase dosage of 10%, an oxidation time of 6 h, an OTN:SM mass ratio of 0.5:1, and a hot-pressing temperature of 160 °C, plywood bonded with OTS exhibited a wet shear strength of 0.85 MPa at 63 °C, representing a 136% increase over that of the neat soybean meal adhesive, and showed slightly higher bonding performance than the commercial urea-formaldehyde (UF) resin under boiling-water conditions. Structural analyses (FT-IR and XPS) verified quinone formation and carbon–nitrogen single and double bonds. Thermal analyses (DSC and TGA) revealed improved curing reactivity and significantly enhanced thermal stability compared with the neat soybean meal adhesive. Full article

Delamination remains a critical limitation in the structural application of wood, particularly in adhesively bonded joints. This study investigates the use of a cyclic olefin-based hot-melt film adhesive (Zeon^® LS-XU) as a thermoplastic interlayer as a means to delay delamination and enhance joint performance. Single lap joints (SLJs) were tested under quasi-static (1 mm/min) and impact (3 m/s) loading to assess strain-rate effects. Six configurations were examined: two reference, two toughened (with an additional 15 mm of adhesive on each overlap side) and two hybrid configurations combining oak (Quercus alba) and pine (Pinus pinaster Aiton) substrates to improve stress wave propagation. A finite element elastic model was developed to analyse stress distributions and explain the superior performance of hybrid joints. Results revealed that the thermoplastic interlayer delayed delamination onset and increased energy absorption, while hybrid configurations achieved more uniform stress distributions and significantly higher strengths under dynamic loading. The most effective configuration, the hybrid joint under impact conditions, represents a strength improvement of approximately 84% of the peak load compared to the pine reference joints. Overall, introducing a thermoplastic interlayer offers an efficient and lightweight strategy to enhance the toughness and reliability of wood joints exposed to variable loading conditions. Full article

Conventional adhesives for plywood are mostly derived from petroleum-based materials and commonly suffer from formaldehyde emission, posing threats to the environment and human health. In this study, a renewable resource, Xanthoceras sorbifolium Bunge oil, was used as the raw material. A high-performance bio-based adhesive was successfully prepared by synthesizing Xanthoceras sorbifolium Bunge oil dimethacrylate (MXOEA) as a reactive diluent, blending it with acrylated epoxy Xanthoceras sorbifolium Bunge oil (AEXO), and introducing 2-isocyanatoethyl methacrylate (IEM) to enhance crosslinking. The effects of the MXOEA/AEXO ratio and the IEM addition level on the properties of the adhesive and the resulting plywood were systematically investigated. The results showed that when the mass ratio of AEXO to MXOEA was 3:7, and the IEM content was 10%, the adhesive exhibited the best bonding performance: the resulting plywood achieved a modulus of rupture of 68.85 MPa, a modulus of elasticity of 8086 MPa, and dry and wet bonding strengths of 3.21 MPa and 2.32 MPa, respectively. Mechanistic analysis indicated that the introduction of IEM moderately reduced the viscosity of the adhesive system. Meanwhile, the isocyanate groups in IEM reacted with the hydroxyl groups on the wood surface, forming a chemical crosslinking structure at the adhesive-wood interface, which is considered one of the reasons for the improved mechanical properties of the plywood. This study provides a formaldehyde-free, high-performance bio-based adhesive derived from Xanthoceras sorbifolium Bunge oil for the field of wood-based composites. Full article